Carbon nanotube-reinforced solder caps,  methods of assembling same, and chip packages and systems containing same

ABSTRACT

A carbon nanotube solder is formed on a substrate of an integrated circuit package. The carbon nanotube solder exhibits high heat and electrical conductivities. The carbon nanotube solder is used as a solder microcap on a metal bump for communication between an integrated circuit device and external structures.

TECHNICAL FIELD

Embodiments relate generally to integrated circuit fabrication. Moreparticularly, embodiments relate to solder cap materials in connectionwith microelectronic devices.

TECHNICAL BACKGROUND

Solders are an important part of a packaged integrated circuit (IC). AnIC die is often fabricated into a microelectronic device such as aprocessor. The solders complete couplings between the IC die and theoutside world.

The increasing demands upon an IC to perform at high speeds and to notoverheat presents problems for the solders. The increasing heat stressesin an IC package causes thermal stresses between the solders and thesubstrates to which the solders are bonded.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to depict the manner in which the embodiments are obtained, amore particular description of embodiments briefly described above willbe rendered by reference to specific embodiments that are illustrated inthe appended drawings. Understanding that these drawings depict onlytypical embodiments that are not necessarily drawn to scale and are nottherefore to be considered to be limiting of its scope, the embodimentswill be described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 is a process depiction during formation of carbonnanotube-impregnated solder particles according to an embodiment;

FIG. 2 is a cross-section elevation of a package that includes a microsolder cap disposed upon a metal bump according to an embodiment;

FIG. 2 is a cross-section elevation of a package that includes a carbonnanotube solder cap disposed upon a metal bump according to anembodiment;

FIG. 3 is a cross-section elevation of a disposed upon a metal bumpaccording to an embodiment;

FIG. 4A is a cross-section elevation of preparing a carbon nanotubesolder particle for bonding according to an embodiment;

FIG. 4B is a cross-section elevation of preparing the carbon nanotubesolder particle depicted in FIG. 4A after further processing accordingto an embodiment;

FIG. 4C is a cross-section elevation of preparing the carbon nanotubesolder particle depicted in FIG. 4B after further processing;

FIG. 4D is a cross-section elevation of preparing the carbon nanotubesolder particle depicted in FIG. 4C after further processing;

FIG. 5A is a cross-section elevation of thermo compression bonding acarbon nanotube solder particle according to an embodiment;

FIG. 5B is a cross-section elevation of thermo compression bonding thecarbon nanotube solder particle depicted in FIG. 5A after furtherprocessing according to an embodiment;

FIG. 5C is a cross-section elevation the carbon nanotube solder particledepicted in FIG. 5B after thermo compression bonding;

FIG. 6( a) is a computer-image depiction of a photomicrograph thatexhibits carbon nanotube solder particles disposed upon a metal bumpaccording to an embodiment;

FIG. 6( b) is a computer-image cross-section elevation depiction of aphotomicrograph that exhibits a carbon nanotube solder particle disposedupon a metal bump according to an embodiment;

FIG. 7A is a cross-section elevation of a carbon nanotube solderparticle after thermo compression bonding according to an embodiment;

FIG. 7B is a cross-section elevation of the structure depicted in FIG.7A after solder cap reflow according to an embodiment;

FIG. 8( a) is a computer-image depiction of a photomicrograph thatexhibits reflowed carbon nanotube solder particles disposed upon a metalbump according to an embodiment;

FIG. 8( b) is a computer-image cross-section elevation depiction of aphotomicrograph that exhibits reflowed carbon nanotube solder particlesdisposed upon a metal bump according to an embodiment;

FIG. 9A is a cross-section elevation of a structure after solder capreflow according to an embodiment;

FIG. 9B is a computer-image cross-section elevation depiction of aphotomicrograph that exhibits a solder-cap-on-solder-cap configurationof carbon nanotube solder particles disposed upon metal bumps accordingto an embodiment;

FIG. 10 is a cross-section elevation of a chip package that exhibits asolder-cap-on-solder-cap configuration of carbon nanotube solderparticles disposed upon metal bumps according to an embodiment;

FIG. 11A is a cross-section elevation of a structure after solder capreflow according to an embodiment;

FIG. 11B is a computer-image cross-section elevation depiction of aphotomicrograph that exhibits a solder-cap-on-bond-pad configuration ofcarbon nanotube solder particles disposed upon a metal bump according toan embodiment;

FIG. 12 is a cross-section elevation of a chip package that exhibits asolder-cap-on-bond-pad configuration of carbon nanotube solder particlesdisposed upon a metal bump according to an embodiment;

FIG. 13 is a process flow depiction of forming a carbon nanotube soldercap according to an embodiment;

FIG. 14 is a cut-away elevation that depicts a computing systemaccording to an embodiment; and

FIG. 15 is a schematic of a computing system according to an embodiment.

DETAILED DESCRIPTION

Embodiments in this disclosure relate to a carbon nanotube solder(CNT-S) cap that is coupled to an IC substrate. One way to improveelectrical and heat conductivity is to improve the electrical and heatconductivity in the solder bumps that are used to connect an IC package.Bonding of a CNT-S particle is done at a temperature that approaches thehomologous temperature.

The following description includes terms, such as upper, lower, first,second, etc. that are used for descriptive purposes only and are not tobe construed as limiting. The embodiments of an apparatus or articledescribed herein can be manufactured, used, or shipped in a number ofpositions and orientations.

Reference will now be made to the drawings wherein like structures willbe provided with like suffix reference designations. In order to showthe structures of various embodiments most clearly, the drawingsincluded herein are diagrammatic representations of integrated circuitstructures. Thus, the actual appearance of the fabricated structures,for example in a photomicrograph, may appear different while stillincorporating the essential structures of the illustrated embodiments.Moreover, the drawings show only the structures necessary to understandthe illustrated embodiments. Additional structures known in the art havenot been included to maintain the clarity of the drawings.

FIG. 1 is a process depiction 100 during formation of carbonnanotube-impregnated solder particles according to an embodiment. A CNTreservoir 110 contains a collection of CNT fibers 112 that are to bemingled with solder. A solder crucible 114 contains molten solder 116.An atomizing gas is introduced at a gas-liquid orifice 118 that causesthe molten solder to atomize into particles in a size range from about 5nanometer (nm) to about 15 nm. In an embodiment, an average particlesize that is formed during atomizing of the molten solder 116 is about 6nm. In an embodiment and in order to prevent premature solidification ofthe molten solder 116 that is being atomized, the atomizing gas ispreheated. In an embodiment, a coil heat exchanger preheats theatomizing gas by economizing heat exchange with the molten solder 116,such that the atomizing gas is virtually the same temperature as themolten solder 116 as it exits at the gas-liquid orifice 118. Theatomizing gas can be a non-reactive gas such as argon (Ar) or othernon-reactive gases.

After atomizing the molten solder 116 at the gas-liquid orifice 118, theCNT fibers 112 are injected into the atomized solder in a fallingmixture 120. In an embodiment, the temperature of the CNT fibers 112 isslightly below that of the atomized solder, such that the CNT fibers 112have a cooling and solidifying effect upon the falling solder. Thefalling mixture 120 is contained within a chamber 122 and it accumulatesinto a plurality of CNT-S particles 124. The CNT fibers have a dimensionof about 2-8 nm in length according to an embodiment.

In an embodiment, the solder 116 is a copper-based solder such as purecopper, copper-tin, copper-tin-lead, copper-tin-silver,copper-tin-bismuth, copper-tin-indium and others.

In an embodiment, the solder 116 is a nickel-based solder such as purenickel, nickel-tin, nickel-tin-lead, nickel-tin-silver,nickel-tin-bismuth, nickel-tin-indium and others. In an embodiment, thesolder 116 is a nickel-titanium shape-memory alloy such as NITINOL®,manufactured by Johnson-Matthey of Wayne, Pa.

In an embodiment, the solder 116 is a tin-based solder such as pure tin,tin-nickel, tin-lead, tin-indium, tin-lead-nickel, tin-nickel-silver,and others. In an embodiment, the solder 116, by weight percent, isapproximately Sn-10 In-0.6 Cu. In this depiction, the solder 116includes about 10 percent indium, about 0.6 percent copper, and thebalance tin. Other impurities may be present, based upon the specificfeedstocks obtained and the chemical purities thereof.

In an embodiment, the solder 116 is an indium-based solder such as pureindium, indium-tin, indium-lead, indium-lead-nickel,indium-nickel-silver, and others.

FIG. 2 is a cross-section elevation of a package 200 that includes amicrosolder cap 210 disposed upon a metal bump 212 according to anembodiment. A bonding pad 214 supports the metal bump 212. A substrate216 supports the metal bump 212. The bonding pad 214 is exposed througha solder mask 218. In an embodiment, the bond pad 214 includes a flashlayer 220, such as a gold flash layer upon a copper bond pad.

In an embodiment, the substrate 216 is an IC die. In an embodiment, thesubstrate 216 is a mounting substrate such as for mounting a flip-chipIC die. In an embodiment, the substrate 216 is a board such as amotherboard.

In an embodiment, the size of the metal bump 212 can be ascertained bythe size of the bond pad 214. In an embodiment, the bond pad 214 isabout 106 micrometers (μm). Other dimensions can be selected dependingupon the application. For example, spacing 220 between centers of bondpads 214 can be less than about 100 μm. In an embodiment, spacing 220between centers of bond pads 214 is about 90 μm.

In an embodiment, the solder cap 210 is derived from a nano-particulatesolder paste, about 100 percent of which pass the 20 nm screening, andthe matrix includes a paste such as a fluxing agent and a volatilecomponent. After reflow, the microsolder cap 210 exhibits an averagegrain size of about 20 μm.

FIG. 3 is a cross-section elevation of a package 300 that includes acarbon nanotube solder cap 310 disposed upon a metal bump 312 accordingto an embodiment. A bonding pad 314 supports the metal bump 312. Asubstrate 316 supports the metal bump 312. The bonding pad 314 isexposed through a solder mask 318. A network 322 of carbon nanotubes isdispersed in the solder cap 310. In an embodiment, the network 322 ofcarbon nanotubes is present in the solder of the solder cap 310 in arange from about 1 to about 99 volume percent of the solder cap 310. Inan embodiment, the network 322 of carbon nanotubes is present in thesolder of the solder cap 310 in a range from about 10 to about 70 volumepercent. In an embodiment, the network 322 of carbon nanotubes ispresent in the solder of the solder cap 310 in a range from about 20 toabout 50 volume percent. In an embodiment, the network 322 of carbonnanotubes is present in the solder of the solder cap 310 in a range fromabout 30 to about 40 volume percent.

In an embodiment, the bonding pad 314 includes a flash layer 320, suchas a gold flash layer upon a copper bond pad. In an embodiment, thesubstrate 316 is an IC die. In an embodiment, the substrate 316 is amounting substrate such as for mounting a flip-chip IC die. In anembodiment, the substrate 316 is a board such as a motherboard.

In an embodiment, the size of the metal bump 312 can be ascertained bythe size of the bond pad 314. In an embodiment, the bond pad 314 isabout 106 μm. Other dimensions can be selected depending upon theapplication. For example, spacing 320 between centers of bond pads 314can be less than about 100 μm. In an embodiment, spacing 320 betweencenters of bond pads 314 is about 90 μm.

FIG. 4A is a cross-section elevation of a method 400 for preparing acarbon nanotube solder particle for bonding according to an embodiment.A rigid substrate 424 has received a layer of CNT-S particles 410according to any of the embodiments set forth in this disclosure. In anembodiment, the CNT-S particles 410 form a monolayer over the rigidsubstrate 424, such that a monolayer can be transferred to a metal bump.Accordingly, the monolayer of CNT-S particles 412 will form a microCNT-S cap that is proportional to the particle size of the CNT-Sparticles 412.

FIG. 4B is a cross-section elevation of the method for preparing thecarbon nanotube solder particle depicted in FIG. 4A after furtherprocessing according to an embodiment. The method 401 illustrates aflexible sheet 426 being brought toward the CNT-S particles 410. Theflexible sheet 426 has an adhesive 428.

FIG. 4C is a cross-section elevation of preparing the carbon nanotubesolder particle depicted in FIG. 4B after further processing. The method402 illustrates the flexible sheet 426 being pressed against the CNT-Sparticles 410. Consequently, a transfer of the CNT-S particles 410 isachieved by the adhesive 428 picking up the CNT-S particles 410 from thesurface of the rigid substrate 424.

FIG. 4D is a cross-section elevation of preparing the carbon nanotubesolder particle depicted in FIG. 4C after further processing. The method403 illustrates the flexible sheet 426 being drawn away from the rigidsubstrate 424 with the CNT-S particles 410 affixed to the adhesive 428and the flexible sheet 426.

FIG. 5A is a cross-section elevation of thermo compression bonding acarbon nanotube solder particle according to an embodiment. A bondingpad 514 supports a metal bump 512. A substrate 516 supports the bondingpad 514. The bonding pad 514 is exposed through a solder mask 518.

A flexible sheet 526 and an adhesive 528 hold a layer of CNT-S particles510 that includes a network of carbon nanotubes dispersed in the CNT-Sparticles 510. The process 500 is illustrated with a thermal compressionhead 530 depicted being brought close to the metal bump 512, with theCNT-S particles 510 approaching the metal bump 512.

FIG. 5B is a cross-section elevation of thermo compression bonding thecarbon nanotube solder particle depicted in FIG. 5A after furtherprocessing according to an embodiment. The process 501 is furtherillustrated with the thermal compression head 530 pressing the CNT-Sparticles 510 against the metal bump 512. In an embodiment, thetemperature of the CNT-S particles 510 is controlled not to exceed themelting point of thereof. Particularly because compression can causeheating, as well as thermal flux being driven out of the thermalcompression head 530 such as by an electrical coil contained therein,temperature control takes both heating effects into account. In anembodiment, the temperature of the CNT-S particles 510 does not exceedabout 99 percent of the homologous temperature, which is the achievedtemperature (in absolute scale) divided by the solidus temperature. Inother words, the solidus temperature, which is the temperature at whicha solid starts to become a liquid at standard atmospheric pressure, isnot reached. In an embodiment, the temperature of the CNT-S particles510 does not exceed about 99.9 percent of the homologous temperature.

FIG. 5C is a cross-section elevation of the carbon nanotube solderparticle depicted in FIG. 5B after thermo compression bonding. Theprocess 502 is further illustrated with the thermal compression head 530retracting from the CNT-S particles, some of which CNT-S particles 511remain disposed against the metal bump 512, and some of which CNT-Sparticles 510 remain disposed against the adhesive 528.

FIG. 6A is a computer-image depiction of a photomicrograph 600 thatexhibits carbon nanotube solder particles 611 disposed upon a metal bump612 according to an embodiment. The CNT-S particles 611 have beenthermal compression bonded to the metal bump 612.

FIG. 6B is a computer-image cross-section elevation depiction of aphotomicrograph 601 that exhibits a carbon nanotube solder particle 611disposed upon a metal bump 612 according to an embodiment. Thecomputer-image of FIG. 6B is more enlarged than the computer-image ofFIG. 6A. The CNT-S particle 611 shows a thermal compression bond line632 between the CNT-S particle 611 and the metal bump 612.

FIG. 7A is a cross-section elevation of a carbon nanotube solderparticle after thermo compression bonding according to an embodiment. Apackage 700 is illustrated with some CNT-S particles 711 remainingthermal compression bonded against a metal bump 712. A bonding pad 714supports the metal bump 712. A substrate 716 supports the bonding pad714. The bonding pad 714 is exposed through a solder mask 718.

FIG. 7B is a cross-section elevation of the structure depicted in FIG.7A after solder cap reflow according to an embodiment. The package 701is illustrated after reflow of CNT-S particles into a CNT-S microcap710.

FIG. 8A is a computer-image depiction of a photomicrograph 800 thatexhibits reflowed carbon nanotube solder particles disposed upon a metalbump according to an embodiment. Reflowed CNT-S particles have formed aCNT-S microcap 810, disposed and bonded to a metal bump 812.

FIG. 8B is a computer-image cross-section elevation depiction of aphotomicrograph 801 that exhibits reflowed carbon nanotube solderparticles disposed upon a metal bump according to an embodiment. Thecross section shows the CNT-S microcap 810, the metal bump 812, andpenetration of a portion of the metal bump 812 onto a bonding pad 814.

FIG. 9A is a cross-section elevation of a package 900 after solder capreflow according to an embodiment. In a first structure 908, a firstCNT-S microcap 910 is disposed upon a first metal bump 912. A firstbonding pad 914 supports the first metal bump 912. A first substrate 916supports the first bonding pad 914. The first bonding pad 914 is exposedthrough a first solder mask 918. In an embodiment, the first substrate916 is an IC die. In an embodiment, the first substrate 916 is amounting substrate such as for mounting a flip-chip IC die. In anembodiment, the first substrate 916 is a board such as a motherboard.

In a second structure 906, a second CNT-S microcap 950 is disposed upona second metal bump 952. A second bonding pad 954 supports the secondmetal bump 952. A second substrate 956 supports the second bonding pad954. The second bonding pad 954 is exposed through a second solder mask958. In an embodiment, the second substrate 956 is an IC die. In anembodiment, the second substrate 956 is a mounting substrate such as formounting a flip-chip IC die. In an embodiment, the second substrate 956is a board such as a motherboard.

The package 900 is depicted being brought together such that the firstmetal bump 912 and the second metal bump 952 are to be in direct contactwith the first solder cap 910. Similarly, the first metal bump 912 andthe second metal bump 952 are to be in direct contact with the secondsolder cap 950. This is because the first solder cap 910 and the secondsolder cap 950 are to meld and form a continuous reflowed CNT-Smicrocap.

Processing of the first solder cap 910 and the second solder cap 950 canbe done by heating the solder cap materials to a low temperature atwhich the solder cap materials begin to reflow.

FIG. 9B is a computer-image cross-section elevation depiction of aphotomicrograph 901 that exhibits a solder-cap-on-solder-capconfiguration of carbon nanotube solder particles disposed upon metalbumps according to an embodiment. After bringing the structures 908 and906 together (FIG. 9A), and after reflowing the two CNT-S microcaps 910and 950, a structure results that is a configuration of the first CNT-Smicrocap 910 disposed and melded with the second CNT-S microcap 950. Theconjoined CNT-S microcaps 910 and 950 appear in FIG. 9B as a bond line960.

FIG. 10 is a cross-section elevation of a chip package 1000 thatexhibits a solder-cap-on-solder-cap configuration of carbon nanotubesolder particles disposed upon metal bumps according to an embodiment.

In a first structure 1008, a first CNT-S microcap 1010 is disposed upona first metal bump 1012. A first bonding pad 1014 supports the firstmetal bump 1012. A first substrate 1016 supports the first bonding pad1014. In an embodiment, the first substrate 1016 is a mounting substratesuch as for mounting a flip-chip IC die.

In a second structure 1006, a second CNT-S microcap 1050 is disposedupon a second metal bump 1052. A second bonding pad 1054 supports thesecond metal bump 1052. A second substrate 1056 supports the secondbonding pad 1054. In an embodiment, the second substrate 1056 is an ICdie that is flip-chip mounted to the first substrate 1016.

FIG. 11A is a cross-section elevation of a package 1100 after solder capreflow according to an embodiment. In a first structure 1108, a firstbonding pad 1114 is disposed on a first substrate 1116. The firstbonding pad 1114 is exposed through a first solder mask 1118. In anembodiment, the first substrate 1116 is an IC die. In an embodiment, thefirst substrate 1116 is a mounting substrate such as for mounting aflip-chip IC die. In an embodiment, the first substrate 1116 is a boardsuch as a motherboard.

In a second structure 1106, a second CNT-S microcap 1150 is disposedupon a second metal bump 1152. A second bonding pad 1154 supports thesecond metal bump 1152. A second substrate 1156 supports the secondbonding pad 1154. The second bonding pad 1154 is exposed through asecond solder mask 1158. In an embodiment, the second substrate 1156 isan IC die. In an embodiment, the second substrate 1156 is a mountingsubstrate such as for mounting a flip-chip IC die. In an embodiment, thesecond substrate 1156 is a board such as a motherboard.

The package 1100 is depicted being brought together such that the firstbonding pad 1114 and the second metal bump 1152 are to be in directcontact with the second solder cap 1150. This is because the firstbonding pad 1114 and the second solder cap 1150 are to meld and form acontinuous reflowed CNT-S microcap.

Processing of the second solder cap 1150 can be done by heating thesolder cap materials to a low temperature at which the solder capmaterials begin to reflow.

FIG. 11B is a computer-image cross-section elevation depiction of aphotomicrograph 1101 that exhibits a solder-cap-on-solder-capconfiguration of carbon nanotube solder particles disposed upon a metalbump according to an embodiment. After bringing the structures 1108 and1106 together (FIG. 11A), and after reflowing the second CNT-S microcap1150, a structure results that is a configuration of the first bondingpad 1114 with the second CNT-S microcap 1150 disposed and meldedtherewith, and also with the second bonding pad 1154.

FIG. 12 is a cross-section elevation of a chip package 1200 thatexhibits a solder-cap 1250 on a bond pad 1254 configuration of carbonnanotube solder particles disposed upon a metal bump 1252 according toan embodiment.

In a first structure 1208, a first substrate 1216 supports a firstbonding pad 1214. In an embodiment, the first substrate 1216 is amounting substrate such as for mounting a flip-chip IC die.

A second CNT-S microcap 1250 is disposed upon a metal bump 1252. Asecond bonding pad 1254 supports the second metal bump 1252. A secondsubstrate 1256 supports the second bonding pad 1254. In an embodiment,the second substrate 1256 is an IC die that is flip-chip mounted to thesecond substrate 1256.

FIG. 13 is a process flow 1300 depiction of forming a carbon nanotubesolder cap according to an embodiment.

At 1308, the process includes mingling CNT fibers with an atomizedsolder to form a CNT-S particle.

At 1310, the process includes forming a plurality of CNT-S particlesupon a rigid substrate.

At 1312, the process includes forming a monolayer of CNT-S particlesupon a rigid substrate.

At 1314, the process includes affixing the CNT-S composite particlesupon an adhesive that is backed by a transfer substrate.

At 1320, the process includes thermo compression transfer bonding theCNT-S composite particle from a transfer substrate to a metal bump. Inan embodiment, the process commences and terminates at 1320.

At 1322, the process includes the thermo compression transfer bonding ata temperature that is below the homologous temperature of the CNT-S. Inan embodiment, the process commences at 1320 and terminates at 1322.

At 1330, the process includes reflowing the CNT-S upon the metal bump toform a CNT-S microcap. In an embodiment, the process commences at 1320and terminates at 1330.

At 1340, the process includes bonding the reflowed CNT-S microcap to oneof a second metal bump and a bonding pad. In an embodiment, the processcommences at 1308 and terminates at 1340. In an embodiment, the processcommences at 1310 and terminates at 1340. In an embodiment, the processcommences at 1320 and terminates at 1340. In an embodiment, the processcommences and terminates at 1340.

FIG. 14 is a cut-away elevation that depicts a computing system 1400according to an embodiment. One or more of the foregoing embodiments ofthe CNT-S microcaps may be utilized in a computing system, such as acomputing system 1400 of FIG. 14. Hereinafter any CNT-S microcapembodiments alone or in combination with any other embodiment can bereferred to as an embodiment(s) configuration.

The computing system 1400 includes at least one IC processor, which isenclosed in a package 1410, a data storage system 1412, at least oneinput device such as a keyboard 1414, and at least one output devicesuch as a monitor 1416, for example. The computing system 1400 includesa processor that processes data signals, and may include, for example, amicroprocessor, available from Intel Corporation. In addition to thekeyboard 1414, the computing system 1400 can include another user inputdevice such as a mouse 1418, for example.

For purposes of this disclosure, a computing system 1400 embodyingcomponents in accordance with the claimed subject matter may include anysystem that utilizes a microelectronic device system, which may include,for example, at least one of the CNT-S microcap embodiments that iscoupled to data storage such as dynamic random access memory (DRAM),polymer memory, flash memory, and phase-change memory. In thisembodiment, the embodiment(s) is coupled to any combination of thesefunctionalities by being coupled to a processor. In an embodiment,however, an embodiment(s) configuration set forth in this disclosure iscoupled to any of these functionalities. For an example embodiment, datastorage includes an embedded DRAM cache on a die. Additionally in anembodiment, the embodiment(s) configuration that is coupled to theprocessor (not pictured) is part of the system with an embodiment(s)configuration that is coupled to the data storage of the DRAM cache.Additionally in an embodiment, an embodiment(s) configuration is coupledto the data storage system 1412.

In an embodiment, the computing system 1400 can also include a die thatcontains a digital signal processor (DSP), a micro controller, anapplication specific integrated circuit (ASIC), or a microprocessor. Inthis embodiment, the embodiment(s) configuration is coupled to anycombination of these functionalities by being coupled to a processor.For an example embodiment, a DSP (not pictured) is part of a chipsetthat may include a stand-alone processor and the DSP as separate partsof the chipset on a board 1420. In this embodiment, an embodiment(s)configuration is coupled to the DSP, and a separate embodiment(s)configuration may be present that is coupled to the processor in thepackage 1410. Additionally in an embodiment, an embodiment(s)configuration is coupled to a DSP that is mounted on the same board 1420as the package 1410. It can now be appreciated that the embodiment(s)configuration can be combined as set forth with respect to the computingsystem 1400, in combination with an embodiment(s) configuration as setforth by the various embodiments of the CNT-S microcaps within thisdisclosure and their equivalents.

FIG. 15 is a schematic of a computing system according to an embodiment.The electronic system 1500 as depicted can embody the computing system1400 depicted in FIG. 14, including a CNT-S microcap embodiment, but theelectronic system is depicted more generically. The electronic system1500 incorporates at least one electronic assembly 1510, such as an ICpackage illustrated in FIGS. 9A, 10, 11A, and 12. In an embodiment, theelectronic system 1500 is a computer system that includes a system bus1520 to electrically couple the various components of the electronicsystem 1500. The system bus 1520 is a single bus or any combination ofbusses according to various embodiments. The electronic system 1500includes a voltage source 1530 that provides power to the integratedcircuit 1510. In some embodiments, the voltage source 1530 suppliescurrent to the integrated circuit 1510 through the system bus 1520.

The integrated circuit 1510 is electrically coupled to the system bus1520 and includes any circuit, or combination of circuits according toan embodiment. In an embodiment, the integrated circuit 1510 includes aprocessor 1512 that can be of any type. As used herein, the processor1512 means any type of circuit such as, but not limited to, amicroprocessor, a microcontroller, a graphics processor, a digitalsignal processor, or another processor. Other types of circuits that canbe included in the integrated circuit 1510 are a custom circuit or anASIC, such as a communications circuit 1514 for use in wireless devicessuch as cellular telephones, pagers, portable computers, two-way radios,and similar electronic systems. In an embodiment, the integrated circuit1510 includes on-die memory 1516 such as SRAM. In an embodiment, theintegrated circuit 1510 includes on-die memory 1516 such as eDRAM.

In an embodiment, the electronic system 1500 also includes an externalmemory 1540 that in turn may include one or more memory elementssuitable to the particular application, such as a main memory 1542 inthe form of RAM, one or more hard drives 1544, and/or one or more drivesthat handle removable media 1546 such as diskettes, compact disks (CDs),digital video disks (DVDs), flash memory keys, and other removable mediaknown in the art.

In an embodiment, the electronic system 1500 also includes a displaydevice 1550, an audio output 1560. In an embodiment, the electronicsystem 1500 includes a controller 1570, such as a keyboard, mouse,trackball, game controller, microphone, voice-recognition device, or anyother device that inputs information into the electronic system 1500.

As shown herein, integrated circuit 1510 can be implemented in a numberof different embodiments, including an electronic package, an electronicsystem, a computer system, one or more methods of fabricating anintegrated circuit, and one or more methods of fabricating an electronicassembly that includes the integrated circuit and the foamed-solderembodiments as set forth herein in the various embodiments and theirart-recognized equivalents. The elements, materials, geometries,dimensions, and sequence of operations can all be varied to suitparticular packaging requirements.

It can now be appreciated that CNT-S microcap embodiments set forth inthis disclosure can be applied to devices and apparatuses other than atraditional computer. For example, a die can be packaged with anembodiment(s) configuration, and placed in a portable device such as awireless communicator or a hand-held device such as a personal dataassistant and the like. Another example is a die that can be packagedwith an embodiment(s) configuration and placed in a vehicle such as anautomobile, a locomotive, a watercraft, an aircraft, or a spacecraft.

The Abstract is provided to comply with 37 C.F.R. § 1.72(b) requiring anabstract that will allow the reader to quickly ascertain the nature andgist of the technical disclosure. It is submitted with the understandingthat it will not be used to interpret or limit the scope or meaning ofthe claims.

In the foregoing Detailed Description, various features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the claimed embodiments of the inventionrequire more features than are expressly recited in each claim. Rather,as the following claims reflect, inventive subject matter lies in lessthan all features of a single disclosed embodiment. Thus the followingclaims are hereby incorporated into the Detailed Description, with eachclaim standing on its own as a separate preferred embodiment.

It will be readily understood to those skilled in the art that variousother changes in the details, material, and arrangements of the partsand method stages that have been described and illustrated in order toexplain the nature of this invention may be made without departing fromthe principles and scope of the invention as expressed in the subjoinedclaims.

1. An article comprising: a solder cap disposed upon a solder bump, wherein the solder cap includes a network of carbon nanotubes dispersed therein; and a bonding pad disposed below and in contact with the solder bump.
 2. The article of claim 1, wherein the network of carbon nanotubes is present in a range from about 1 to about 99 volume percent in the solder cap.
 3. The article of claim 1, wherein the network of carbon nanotubes is present in a range from about 20 to about 50 volume percent in the solder cap, wherein the solder cap is a first solder cap, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the article further including: a second bonding pad coupled to the first solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board, wherein the second bonding pad is in direct contact with a second solder cap, and wherein the second solder cap is in direct contact with the first solder cap.
 4. The article of claim 1, wherein the bonding pad is a bonding pad for one of a microelectronic device, a mounting substrate, and a board.
 5. The article of claim 1, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the article further including: a second bonding pad coupled to the solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board.
 6. The article of claim 1, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the article further including: a second bonding pad coupled to the solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board, and wherein the second bonding pad is in direct contact with the solder cap.
 7. The article of claim 1, wherein the solder cap is a first solder cap, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the article further including: a second bonding pad coupled to the first solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board, wherein the second bonding pad is in direct contact with a second solder cap, and wherein the second solder cap is in direct contact with the first solder cap.
 8. A process comprising: thermo compression transfer bonding a carbon nanotube-solder (CNT-S) composite particle from a transfer substrate to a solder bump.
 9. The process of claim 8, further including reflowing the CNT-S upon the solder bump.
 10. The process of claim 8, further including: reflowing the CNT-S upon the solder bump to achieve a reflowed CNT-S and solder bump; and bonding the reflowed CNT-S and solder bump to a bonding pad.
 11. The process of claim 8, further including: reflowing the CNT-S upon the solder bump to achieve a reflowed first CNT-S and solder bump; and bonding the reflowed first CNT-S and solder bump to a second solder bump.
 12. The process of claim 8, wherein thermo compression transfer bonding is carried out below the homologous temperature of the CNT-S.
 13. The process of claim 8, wherein thermo compression transfer bonding is preceded by affixing the CNT-S composite particle upon an adhesive.
 14. The process of claim 8, wherein thermo compression transfer bonding is preceded by: forming a plurality of CNT-S particles upon a rigid substrate; affixing the CNT-S composite particles upon an adhesive layer; and placing the adhesive layer against the transfer substrate.
 15. The process of claim 8, wherein thermo compression transfer bonding is preceded by: forming a monolayer of CNT-S particles upon a rigid substrate; affixing the CNT-S composite particles upon an adhesive layer; and placing the adhesive layer against the transfer substrate.
 16. The process of claim 8, wherein thermo compression transfer bonding is preceded by mingling CNT fibers with a solder to form the CNT-S particle.
 17. A computing system comprising: a die and coupled to the die; a solder cap disposed upon a solder bump, wherein the solder cap includes a network of carbon nanotubes dispersed therein; a bonding pad disposed below and in contact with the solder bump; and dynamic random-access memory coupled to the die through the foamed solder.
 18. The computing system of claim 17, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the computing system further including: a second bonding pad coupled to the solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board.
 19. The computing system of claim 17, wherein the bonding pad is a first bonding pad for one of a first microelectronic device, a first mounting substrate, and a first board, the computing system further including: a second bonding pad coupled to the solder cap, wherein the second bonding pad is integral to one of a second microelectronic device, a second mounting substrate, and a second board, and wherein the second bonding pad is in direct contact with the solder cap.
 20. The computing system of claim 17, wherein the computing system is disposed in one of a computer, a wireless communicator, a hand-held device, an automobile, a locomotive, an aircraft, a watercraft, and a spacecraft.
 21. The computing system of claim 17, wherein the microelectronic die is selected from a data storage device, a digital signal processor, a micro controller, an application specific integrated circuit, and a microprocessor. 